Well, my car is a '93 base model with 113k miles on it.

Engine just replaced ~2.5k miles ago

My mods are: PFC, PFS Intercooler, Custom Intake, DP, Blitz Nur-Spec Cat-back.

After having the engine installed I was having some drivability issues & the car failed emissions both for idle & at 2.5k rpms. I knew there wasn't something right so I took it to kd rotary and had them check it out they replaced my wiring harness and fixed a vacuum line or to. It appears to be driving better now, but I went and had it reinspected with the following results:

Reading Limit
HC(low) 12 220
HC(high) 790 220
CO(low) 0 1.2
CO(high) 7.2 1.2

As you can see the idle is fine, but the higher rpm reading are bad. I don't think it is my cat since the low #s are fine, I will try replacing the spark plugs, and may try putting the stock computer back in. Any other suggestions? My turbos are original and I do get some oil blow by in my intake but I don't think it is enough to cause this problem, I don't see any blue smoke. Any other suggestions or things I can eliminate. Could it be the air pump? Wouldn't that cause issues at idle also?

Thanks for any help.

 

Is the air pump turning off and on?

 

This is pretty basic, but was the engine totally warmed up when it was tested? At least 30 minutes of highway driving or equivalent?

 

^^^^that was my first guess. Get a voltmeter and check the voltage going to the airpump at idle, at 2,000rpm, and at 4,000 rpm. If it is getting a good signal, then it will be a failed airpump. If u dont have a volt meter I guess u can always do the visual check......If u dont hear it click on and off at idle and if the metal portion on the front of the pulley isn't spinning...then I guess u can say its bad. U can usually find a used one from $30-50 depending on whos selling it There might be some in the sale forum

 

The PFC shuts the air pump off at 2500 rpm instead of 3200 rpm like the stock ecu. You are failing the 25 mph test because they are running the test in 2nd gear, which is above 2500 rpm. Have them shift into 3rd and you'll probably pass just fine. You could also just put the stock ecu back in if they refuse to run the car in 3rd gear.

 

another tiny thing, spark plugs maybe? even if they`re very new that can make a big *** difference if they`re fouled...which can happen. on my 2nd gen they had like 1000 miles on em, failed, changed em went back, pass. if nothing else helps its like $20 so maybe worth a try? hopefully its just something simple like that. god i hate emissions. best of luck to you.

 

" PFC shuts the air pump off at 2500 "

does that mean that basically - there is no chance that one could pass the 60 mph test - the one they do in NYC? I guess one could shift at 2400 or something.... ?

 

I have no idea about the NYC test....in Cali the car is put on a dyno and brought up to a constant speed (15 and 25 mph) for several seconds. The average reading over the several seconds of constant speed is your reading. If your test is similar, the tech should shift into 5th gear for the 60 mph test.

 

Change your cat.

 

what about taking 2 stock cats and welding them together. Then extend the air pump pipes to both cats. I think this would work and pass no problem. Only thing I could see is the clearance/fitment underneath the car.

 

Jason, good to see you've still got the FD.

I would agree the air pump, ACV, or one of the solenoids that fire it off could be the problem.

Dave

 

I am going to check out the airpump this weekend, I am also planning on changing the spark plugs.

rynberg-here in delaware they just check two rpms in neutral, no wheels spinning. But, if the pfc does turn the airpump off at 2.5k that could be part of the problem because I held the throttle just above 2.5k, I should try to keep it just below...

Retserof-I was on the highway at ~80 for over a half an hour before stopping to test

I don't appear to be getting very good gas milage either. Haven't done an actual calculation, but the needle is almost at half a tank and I haven't even gone 100miles yet. That seems bad from what I can remember, but it has been a while since I have driven the car regularly. That could be a pinched injector oring, which would also cause the emissions problems, although they checked these and replace one at kd while it was there

Dave, good to here from you.

Thanks everyone for the input so far.

 

Well, I swapped my stock computer back in and passed the emissions test with flying colors without any other changes. In fact, I had my friend check my emissions at his shop before going back to the inspection lane and he said it was the cleanest burning car he has ever seen, he said that the numbers actually went up when he removed the probe from my tail pipe. At the inspection lane the numbers were also very low with a HC reading of 9 and CO was undetectable. This has me a little worried that it is running way too lean with the stock computer though. I plan on putting the pfc back in and leaning it out a bit. It is a little frustrating since I just had it tuned at KD, they are too far to keep driving back up there. I guess very little turns out right on the first try...

 

i changed all my stuff back over the weekend to stock, took it in and i failed although i was driving around town for 45 minutes. my HC was too high then they did it again but b4 doing it they revved my engine at 4500 rpm for like 2-3 mins and i passed jus fine, good luck